Related Experiment Video
Updated: Jul 7, 2026
08:08
Chicken Recombinant Limbs Assay to Understand Morphogenesis, Patterning, and Early Steps in Cell Differentiation
Published on: January 12, 2022
Activator-inhibitor dynamics of vertebrate limb pattern formation
1Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York 10595, USA. newman@NYMC.edu
Birth Defects Research. Part C, Embryo Today : Reviews
|January 30, 2008
Summary
This study explores limb development, revealing a core mechanism for bone pattern formation involving transforming growth factor-beta and fibronectin. A model explains the proximodistal bone emergence and suggests Notch signaling for spatial arrangement.
Area of Science:
- Developmental Biology
- Biophysics
- Molecular Genetics
Background:
- Vertebrate limb development involves complex cellular processes including differentiation, pattern formation, and morphogenesis.
- Existing knowledge identifies numerous genes influencing limb skeletal pattern but lacks principles for its quasiperiodic bone arrangement.
Purpose of the Study:
- To review and present organizational principles governing vertebrate limb skeletal pattern formation.
- To describe a core mechanism for precartilage mesenchymal condensation and a bare-bones model for limb development.
Main Methods:
- Review of concepts from physics, chemical dynamics, molecular genetics, and cell biology.
- Description of a core mechanism involving transforming growth factor-beta (TGF-β) and fibronectin.
- Presentation of a bare-bones model incorporating local autoactivation-lateral inhibition (LALI) and fibroblast growth factor (FGF) signaling.
Main Results:
- A core mechanism for mesenchymal condensation via TGF-β autoregulation, fibronectin induction, and haptotaxis is described.
- A local autoactivation-lateral inhibition (LALI) system ensures regular spacing of condensations.
- A bare-bones model explains proximodistal (PD) bone emergence using defined developmental zones and FGF signaling, with potential lateral inhibition via Notch signaling.
Conclusions:
- Limb development arises from an interplay of molecular genetics and dynamic physical processes.
- The proposed models provide insight into the quasiperiodic arrangement of limb bones and PD patterning.
- Understanding these principles may illuminate the origins of congenital anomalies.
More Related Videos
06:49Analysis of Cell Differentiation, Morphogenesis, and Patterning During Chicken Embryogenesis Using the Soaked-Bead Assay
Published on: January 12, 2022
08:04Application of Impermeable Barriers Combined with Candidate Factor Soaked Beads to Study Inductive Signals in the Chick
Published on: November 17, 2016
Related Concept Videos
01:31Mechanism of Lamellipodia Formation
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
01:09Changes in the Appendicular Skeleton with Age
The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:07Development of the Limb Synovial Joints
Joints form during embryonic development in conjunction with the formation and growth of the associated bones. The embryonic tissue that gives rise to all bones, cartilage, and connective tissues of the body is called mesenchyme.
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
02:33Hedgehog Signaling Pathway
The Hedgehog gene (Hh) was first discovered due to its control of the growth of disorganized, hair-like bristles phenotype in Drosophila, much like hedgehog spines. Hh plays a crucial role in the development of organs and the maintenance of homeostasis in both invertebrates and vertebrates. However, while Drosophila has only one Hh protein, mammals have multiple functional Hedgehog proteins - Sonic (Shh), Desert (Dhh), and Indian Hedgehog (Ihh). All of these homologous proteins have adapted to...
01:51Determination
During embryogenesis, cells become progressively committed to different fates through a two-step process: specification followed by determination. Specification is demonstrated by removing a segment of an early embryo, “neutrally” culturing the tissue in vitro—for example, in a petri dish with simple medium—and then observing the derivatives. If the cultured region gives rise to cell types that it would normally generate in the embryo, this means that it is specified. In contrast, determination...
01:29Bone Formation by Intramembranous Ossification
Intramembranous ossification is one of the two processes involved in the development of bones within an embryo. The flat bones of the face, most of the cranial bones, and the clavicles are formed via this process. During intramembranous ossification, the bones develop directly from sheets of undifferentiated mesenchymal connective tissue.
The process begins when mesenchymal cells in the embryonic skeleton gather together and differentiate into osteogenic cells, which then develop into...
The process begins when mesenchymal cells in the embryonic skeleton gather together and differentiate into osteogenic cells, which then develop into...